1. Dummy router elimination: In the binomial merging process of BMAP
algorithm, it is assumed that the mesh network is of the dimension
2
n
× 2
n such that the number of IP cores k ≤ 2
n
× 2
n . If the number of
cores is less than that of possible routers, in the final network there
will be a few routers to which no core is attached. Such routers constitute dummy routers. Communication between such dummy cores
or routers is zero. Hence, after the iterative merging process, such
routers are put to the boundary of the mesh. These dummy routers
can be removed without sacrificing the network speed. This saves
the area, as well as the power, since the idle routers also consume
static power.
2. Router selection: In an OCN development environment, several alternative router designs may be available, with varying cost, in terms
of area, performance, power, and so on. For example, a router has a
number of channels. Since the buffers are the most costly components (in terms of area and power consumption) of a router, several
trade-offs can be made. For fastest operation, each of the individual input–output channels may have their own buffer. However, a
number of channels can be made to share their buffer space, and
therefore reduce the cost of the router. Buffer depths can also vary.
Routers having low bandwidth cores attached to them may use a
less costly router, whereas the routers having high traffic passing
through them may have separate buffers (with possibly higher
depth) in each channel.
A1
A2
B1
A1
C1
B2
A2
C2
B1
C1
B2
C2
D1
D2
D1
D2
Sixteen merging cases:
A1–A2, A1–B2
A1–C2, A1–D2
B1–A2, B1–B2
(b)
Four merging cases:
B1–B2, B1–C2
C1–B2, C1–C2
B1–C2, B1–D2
C1–A2, C1–B2
C1–C2, C1–D2
D1–A2, D1–B2
(a)
D1–C2, D1–D2
Figure 5.6
Merging of IP sets: (a) 16 cases in d 1 = d 2 ; (b) 4 cases in d 1 ≠ d 2 . (Data from Shen, T., et al., A new
binomial mapping and optimization algorithm for reduced-complexity mesh-based on-chip
network, Proceedings of NOCS’07, 317–322, 2007.)
133
Application Mapping on Network-on-Chip
algorithm, it is assumed that the mesh network is of the dimension
2
n
× 2
n such that the number of IP cores k ≤ 2
n
× 2
n . If the number of
cores is less than that of possible routers, in the final network there
will be a few routers to which no core is attached. Such routers constitute dummy routers. Communication between such dummy cores
or routers is zero. Hence, after the iterative merging process, such
routers are put to the boundary of the mesh. These dummy routers
can be removed without sacrificing the network speed. This saves
the area, as well as the power, since the idle routers also consume
static power.
2. Router selection: In an OCN development environment, several alternative router designs may be available, with varying cost, in terms
of area, performance, power, and so on. For example, a router has a
number of channels. Since the buffers are the most costly components (in terms of area and power consumption) of a router, several
trade-offs can be made. For fastest operation, each of the individual input–output channels may have their own buffer. However, a
number of channels can be made to share their buffer space, and
therefore reduce the cost of the router. Buffer depths can also vary.
Routers having low bandwidth cores attached to them may use a
less costly router, whereas the routers having high traffic passing
through them may have separate buffers (with possibly higher
depth) in each channel.
A1
A2
B1
A1
C1
B2
A2
C2
B1
C1
B2
C2
D1
D2
D1
D2
Sixteen merging cases:
A1–A2, A1–B2
A1–C2, A1–D2
B1–A2, B1–B2
(b)
Four merging cases:
B1–B2, B1–C2
C1–B2, C1–C2
B1–C2, B1–D2
C1–A2, C1–B2
C1–C2, C1–D2
D1–A2, D1–B2
(a)
D1–C2, D1–D2
Figure 5.6
Merging of IP sets: (a) 16 cases in d 1 = d 2 ; (b) 4 cases in d 1 ≠ d 2 . (Data from Shen, T., et al., A new
binomial mapping and optimization algorithm for reduced-complexity mesh-based on-chip
network, Proceedings of NOCS’07, 317–322, 2007.)
133
Application Mapping on Network-on-Chip